''The Poincare Conjecture'' tells the story behind one of the world's most confounding mathematical theories. Formulated in 1904 by Henri Poincare, his Conjecture promised to describe the very shape of the universe, but remained unproved until a huge prize was offered for its solution in 2000. Six years later, an eccentric Russian mathematician had the answer. Here, Donal O'Shea explains the maths behind the Conjecture and its proof, and illuminates the curious personalities surrounding this perplexing conundrum, along the way taking in a grand sweep of scientific history from the ancient Greeks to Christopher Columbus. This is an enthralling tale of human endeavor, intellectual brilliance and the thrill of discovery.